The most widespread medium for distributing motion pictures is the videocassette. However, digitally encoded optical disks are in theory far superior for the distribution of motions pictures and other forms of presentation. Especially advantageous is the use of "compressed video," by which it is possible to digitally encode a motion picture on a disk no larger that the present-day audio CD. Information storage on an optical disk may in fact be so dense that the same disk may contain multiple versions (e.g., R-rated and PG-rated) of the same motion picture, multiple soundtracks in different languages, and data for other related and even unrelated signals.
Because of the different television industry standards used throughout the world, there are an equal number of videocassette standards. An NTSC videotape sold in the United States, for example, will not play on most videocassette players to be found in England. In order for a software publisher not to have to produce optical disks in as many different formats as are presently required for videocassettes, it would be far preferable for the data stored on an optical disk to be converted to a particular standard by the player. That way, the same disk could be sold anywhere in the world. Because of the advantages offered by the storage of digital data on optical disks, it is possible to achieve this flexibility along with the storage of so many different signals.
However, the development of new optical disk formats and complementary players entails a very great expense. Moreover, considerable efforts are required in launching a new carrier format, and at least in the early years, until consumer acceptance grows, profits may be elusive. It is expected that, as the popularity of a new format grows, other software publishers will take advantage of it and produce their carriers in the new format along with the old. This works a hardship on those software publishers who pioneer the new format and do not sit by waiting to see if the new format becomes established.
In order to insure the early participation of as many software publishers as possible, or that those who join later pay their dues, it would be highly advantageous were there a way for the new type of player to play the new type of disk only if the disk is "authorized" by the hardware/software manufacturers who are trying to establish the new format. Were there a way to prevent unauthorized software publishers from distributing disks which would play in the new type of player, then all software publishers who desire to take advantage of the new format would be required to share in the development and initial marketing costs. It is therefore an object of this invention to provide a system and method for preventing the play of unauthorized software carriers in a player.
Once it is possible to prevent any play of an unauthorized optical disk, for example, it becomes possible to carry the lock-out one step further. By this is meant that it becomes possible to prevent certain kinds of play, while permitting others. For example, an optical disk may contain digital data in a format which will allow a compatible player to generate a video signal in any of the world's transmission standards, NTSC, PAL, SECAM, etc. If it is possible to prevent the play of a disk altogether, it should also be possible to allow the play of the disk in order to generate a video signal in one or more authorized standards, while preventing the generation of video signals in other standards. A software publisher whose audio-visual works are geared for a particular territory might be interested, for example, in having his disks play only on SECAM television receivers and no others. Such a publisher should perhaps have to pay less of a license fee than publishers whose disks play on television receivers of all standards. What is necessary in such a case is to provide software manufacturers with the knowledge necessary to manufacture optical disks which play in only selected standards. It is therefore another object of this invention to provide a way in which play of a software carrier in accordance with only selected standards can be authorized.
It must be understood that the principles of the present invention are not limited to any particular types of carriers or any particular kinds of software. It is true that the most widespread use foreseen for the invention is in connection with the development of new optical disk formats. Nevertheless, it is to be understood that the invention is not limited to a particular medium (for example, it is applicable to tape carriers and all digital storage media), nor is it limited to just the distribution of motion pictures. For example, in an extreme case, the invention is applicable to the distribution of a library of still pictures, in which there is no "motion" at all. The term "software publisher" thus embraces much more than a motion picture company, and the term "carrier" embraces much more than a digitally encoded optical disk.